Contributions of a High-Definition, 3D Exoscope System for Skull Base Microneurosurgical Resident and Fellow Education

Background Following our early experiences utilizing a three-dimensional (3D) exo/endoscope for concurrent 3Dneuroendoscopy we have sought to maximize both image quality and ergonomics to move 3D exoscope into the realm of being a primary instrument for skull base approaches and resident/fellow education. Our initial exo/endoscope had an external diameter of 4.7 mm, utilizing a single glass rod optical element allowing for suboptimal 640 × 480 stereoscopic images. Though somewhat immersive, the poor image quality and lack of reproducibility of the anatomy made its use suboptimal. In response to the limitations of endoscopes, contemporary exoscopes, and operative microscopes, a high-definition extracorporeal telescope (exoscope) system was developed in hopes of maximizing the educational experience for assistants and observers, maximizing immersion and reproducibility, and modifying the learning curve for these complex approaches.

Methods Over the past 3 years, we have worked to develop a 3D video microscope with dual complementary metal oxide semiconductor cameras with a resolution of 3,840 × 2,160 pixels that can be displayed on 3D compatible monitors. The monitor used in conjunction with this microscope is a 3,840 × 2,160 resolution prototype monitor which utilizes the 3D LBL output of the system to display full resolution circularly polarized passive 3D images. 4K-HD 3D video can also be recorded and reviewed as needed. Five cadaveric skull base approaches were undertaken at the center for future surgery. Variables evaluated in each approach included operative duration, structure visualization, surgeon and assistant ergonomics, educational contribution, device impact on operating corridors and instrument maneuverability, video quality, immersive experience, learning curve, and operating room logistics for observation.

Results The exoscope had a wide field of view (600 mm) and a mean focal distance of 200–300 mm). This allowed for the passage of standard neurosurgical instruments with relative ease by both the primary and assistant surgeons. It additionally allowed for both the surgeon and cosurgeon, to operate concurrently and interactively while viewing the high-definition video monitors. The surgical experience was reported to be fully immersive. No differences in the duration of the surgical approach or recognition of salient anatomy were noted. The image allowed for the rapid understanding of the salient anatomy in addition to rapid reproduction and review as needed.

Conclusion The current 3D 4K-HD exoscope system has been developed to optimize surgical visualization, while maintaining the ergonomic advantage and maneuverability that the exoscope affords. We described our experience with the novel 3D 4K-HD exoscope system on a series of human cadaveric skull base approaches. We will discuss our experience in hopes of elucidating the ergonomic and visualization benefits of this novel 3D exoscope in skull base approaches and its potential benefits in educating future surgeons with specific interest in approaches to the skull base.